江苏省2008年新课标下高考的备考调查及其分析

2008年6月江苏省将进行新高考,这是江苏省自新课程改革及新高考方案颁布后的第一次高考,全社会极为关注。通过调查苏州、南通、盐城的6所学校的高三学生和化学老师,针对化学新教材的使用、新课标的理解、新高考方案的出台及备战新高考的过程中出现的问题进行全面的分析,并提出了相应的建议和对策。     

2009年安徽省新课标下高考化学备考情况的调查分析与对策

对皖南和皖中地区8所中学的高三学生、高三化学教师以及学生家长面对新高考方案的心理状况进行了调查和了解,同时针对2009年化学新教材使用和新高考备考过程中出现的问题进行全面分析,并提出相应的对策。     

"3+X"高考后特区内高中生学习化学情况调查与对策

自广东省实行“3+Ｘ”高考以后 ,高考试卷与考生的学科流向发生了极大的变化 ,给高中的教学与高考备考都带来了新的挑战与新的问题。对中学的化学学科教学 ,也产生了较大的影响。目前大学招生的热门系科一般都需要考物理与政治学科 ,而由于深圳特区内环境保护方面的原因 ,在就业问题上 ,化学方面的人才需求较少。因此 ,报考化学的学生人数较少 ,成绩优秀的学生一般也不选择学习化学。高中化学教师也在抱怨 ,化学考生素质太差 ,高三化学的教学与复习投入大产出少。教师中存在缺乏信心和无所作为的思想。为了清楚地了解高考改革后对学生学习化…     

高中化学氧化还原反应方程式配平技能学习进阶的探讨

氧化还原反应方程式配平技能是学生需要发展的化学基本技能之一。从学生需要的基础技能、氧化还原反应的复杂性、教科书教学内容的安排、高考的命题和考试要求这4方面讨论了影响氧化还原反应方程式配平技能的因素。对在“化学1”模块阶段、高考总复习阶段中,氧化还原反应方程式配平技能的学习过程进行分析,提出1个包括4个预期水平的预期水平方案。最后分别对围绕氧化还原反应方程式配平技能的教学实践、学术研究提供建议。     

学生选择化学专业的动机调查和研究

学习动机不仅影响学生的学习态度 ,也影响学生将来的学习方向。调查研究表明 ,学生在高考时选择化学专业的主要动机因素来自认知需要、自我提高需要和交往需要 ,分析其中最重要的化学学科成绩、化学实验、化学的社会地位和化学教师四项因素 ,探讨运用动机因素的注意点 ,有助于在化学教学中更好地激发学生学习化学的动机和兴趣 ,开展素质教育 ,全面提高化学教育质量。     

高考化学命题对教材素材的应用与思考

化学教材是教师教学和学生学习的依据,近几年江苏高考化学命题越来越重视教材素材的应用。从近3年的江苏高考化学试题出发,列举了高考命题对教材素材的具体应用,以及由此引发的对平时化学教学的某些思考。     

高考化学复习误区的剖析

针对高考化学卷试题和学生的考试情况,反思高三一年的教学,剖析化学高考复习3大误区:教学内容机械重复;教学手段因袭陈旧;复习缺少人性关怀。     

书写信息型化学方程式的备考策略——2008年高考北京理综化学试题对高三教学的启示

近几年信息型化学方程式在高考化学用语考查中分值逐渐增大。高三化学教师在教学中需从夯实基础、规范表达、细审题目、解题方法、心理素质等方面对学生进行科学训练,使学生在高考时轻松应对,准确书写。     

高中化学必修与选择性必修教材融合的教学策略 ——以 “原子结构与元素周期律”为例

正1教学背景在2017年版新课标与"一核四层四翼"新高考评价体系大背景下,北京市高中化学"学"与"考"的模式为:全体高中学生必须修习4学分的必修课程(化学必修1和必修2),高一学年末参加北京市组织的学业水平"合格性"考试;选择化学计入高校招生录取总成绩的学生还需要修习选择性必修(下称"选必")3个模块的内容,高考参加学业水平"等级性"考试。面对高考选考化学的学生,北京市高二化学教学要完成《化学反应原理》《物质结构与性质》《有机化学基础》3个选必模块教材,每周4课时。     

对2012全国新课标理综高考几个化学热点问题的研究

针对2012全国新课标理综高考人们普遍关注的几个化学热点问题提出了自己的分析意见,分析过程中结合所涉及问题的典型研究、中学教材、学生实际情况给出了一些有利于深化化学教学及高考化学备考的建议。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).